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Top1. Introduction
The phrase ‘Construction and Demolition’(C&D) refers to such waste which is created during the construction and demolition processes. Waste arising from construction and demolition activities in civil and structural engineering, so-called C&D waste, represents a major share of total waste generation, showing its high importance from both waste management and resource efficiency perspectives (Heite, 2013). United States environment protection agency (USEPA) has estimated that averagely, about 136 million tons C&D waste has been created in 1996 that about 48% of that is concerned with demolition processes and about 44% is concerned with renovation processes (Yuan et al., 2011). In Britain about 70 million tons C&D waste is created every year. In 2000 about 10% up to 15% waste created in England that is concerned with buildings (Yuan et al., 2011). In Australia about 16% up to 40% of waste is landfilled in surrounding lands (Yuan et al., 2011). In Hong Kong, in the years 1993 to 2004, creation of waste was about double of the previous years and this amount ran into 20 million tons in 2004 (Yuan et al., 2011).
It has been reported that about 25% of wood and 40% of raw stone and sand are used by building industries in all over the world (Yuan et al., 2012). Creation and production of buildings elements along with construction processes include extraction of 6 billion tons material in United States, annually. Moreover building industry in America injects a huge amount of waste into the flows of municipal solid waste (Yuan et al., 2012). In China C&D waste has been run into 30% up to 40% in urban areas that its reason is a sudden growing up in urbanization (Zhao et al., 2011).
Unorganized and unsorted waste is one of the big impediments in the way of waste management. Regarding the huge amount of waste which has been created in 1980 and even its increasing rate, little continuous efforts have been done for detecting innovative methods and solutions in order to reduce waste and alleviate its negative effects. Moreover, we should consider that among researches have been done yet, analyzing the methods of reducing C&D waste has attracted little attention to itself.
In line with increasing sustainable development as an important principal and also environmental protection, construction industry has been detected as an important parameter and mission in order to reduce unwanted and negative effects of C&D waste on the environment. In order to achieve this aim, need for optimized management is felt. Thus, C&D waste management has attracted a wide attention from practitioners in all over the world.
Negative and inverse impacts of C&D waste are diverse. The most important negative impact could be an increase in landfilling and consequently an increase in the negative impacts on the environment. An increase in landfilling will cause an increase in the costs and also in the space of landfilling fields. For instance about 3500m3 is allocated to waste landfilling daily in Hong Kong (Yuan et al., 2011). In United States, limited capacity of landfilling fields alongside difficulty of developing these fields, has caused growing concerns for regulators and managers (Yuan et al., 2011). Construction and demolition activities are instinctively non-friendly activities for the environment. Many harms to the environment are caused by them and its reason is different negative impacts such as a reduce in natural resources, noise emission, running dust into the air, air pollution and injecting poisonous materials into the environment (Yuan, 2012).
Society is affected from many aspects by C&D waste and the way of managing it. Some of economic impacts include (Ye et al., 2012): Investment in C&D waste management, costs of sorting, cost of purchasing new equipment, and economic profit of recycling waste.
Environmental impacts of C&D waste management include (Ye et al., 2012): Over-extraction of raw materials, destroying agricultural fields in order to landfill waste, infusing pollution and poisonous materials into the water and oil supplies in depth of the earth and noise emission.